Assistive Exosuit Targets Occupational Back Injury

Assistive Exosuit Targets Occupational Back Injury
Device spun off from research lends flexible support for heavy lifting.

Back pain is on the rise, while the choice of treatment is complicated by the risk of opioid reliance for pain relief. Unfortunately, few solutions to prevent back pain have offered solid evidence of benefit. Karl Zelik, Ph.D., assistant professor of physical medicine and rehabilitation at Vanderbilt University Medical Center, has spent several years working on a better system to prevent the debilitating condition.

Zelik is the co-founder and chief scientific officer at HeroWear LLC, which recently launched the Apex exosuit, designed specifically to support men and women in logistics and warehousing jobs. Weighing just 3.4 pounds and assuring customized body fit through 56 potential configurations, the exosuit absorbs up to 43 percent of the muscle force during lifting and bending.

“Our goal was to create a device that seamlessly integrates into the wearer’s life so they can wear it comfortably and only engage assistance when they need back relief during bending or lifting,” Zelik said.

Filling an Innovation Gap

Back injuries account for 20 percent of all workplace injuries, forming the single largest category of worker’s compensation injury. Previous efforts to spare the back through postural-assist devices have made little headway. As long ago as 1996, the National Institute of Occupational Safety and Health (NIOSH) declared that the ubiquitous lumbar back belts employers have relied upon for decades showed no evidence of preventing back injury.

In contrast, exoskeletal suits can effectively offload the musculoskeletal system but have built-in motors and metal struts that make them heavy and bulky. The main adopters have been automotive manufacturers who use shoulder exoskeletons to support workers doing repetitive tasks while standing mostly in one spot.

“The primary goal of the Apex exosuit is to reduce the risk of back injury to a wide variety of workers,” said Aaron Yang, M.D., medical director of outpatient services at Vanderbilt Stallworth Rehabilitation Hospital and co-investigator on the device. “I see people in certain occupations that are more susceptible to back injuries from prolonged or repetitive movements, but also from standing or leaning for long periods of time. For all of these people, this device may have preventative implications.”

“The primary goal of the Apex exosuit is to reduce the risk of back injury to a wide variety of workers.”

How the Technology Works

HeroWear Apex is wearable throughout the day and wherever the worker goes. The lightweight exosuit works by using elastic bands that span along the back, connecting a ventilated textile shoulder harness to breathable sleeves that wrap around each thigh.

“When a person bends down, some of the force is routed through the elastic bands rather than through the person’s own back muscles, relieving strain off the back. During lifting, as a person stands back up, the potential energy stored in the elastic bands is released, which helps the person spring up.” Zelik said.

A clutch mechanism empowers the wearer to quickly engage assistance by pressing a button on their shoulder. Tapping the button again disengages assistance. This enables the wearer to retain their full range of motion, and ensures the exosuit does not interfere with any other aspect of their job.

Zelik’s team has a new study under peer review showing the device can reduce the rate at which lower back muscles fatigue by an average of 30-40 percent. “Reducing peak loads on the back may be most related to reducing injury risks, whereas reducing muscle fatigue may be more related to long-term productivity and the well-being of the workforce,” Zelik said.

New Design Modifications

One of the key goals in designing the Apex exosuit was to ensure an option that fits women as well as men. “We realized that exoskeleton manufacturers have not been developing devices to properly fit women’s bodies. This is a problem since women make up over half of the industrial workforce, so we created a female-specific version of the Apex,” Zelik said.

“We realized that exoskeleton manufacturers have not been developing devices to properly fit women’s bodies.”

Next, Zelik’s team will integrate embedded sensors that monitor musculoskeletal loading and can activate the device’s assistance autonomously. The sensors have the potential to accumulate data and issue warnings when the wearer is overexerting. They are also exploring how to adapt the exosuit to support people in other occupations, such as nurses and surgeons, that have a high incidence of back pain.